1. Field of the Invention
This invention relates to an accessory for a tire changing machine, and more particularly to such an accessory for use when mounting or demounting tires on custom alloy wheel rims.
2. Description of the Prior Art
Tire changers such as the one disclosed in U.S. Pat. No. 4,335,772, Bubik et al, issued June 22, 1982 have a rotatably driven tire tool driving post with a flat tongue portion extending thereabove. After the bead of the tire has been broken from a wheel rim, a tire tool with a slot in the tool body is hooked under the tire bead and over the rim and the tool is then positioned so that the driving post tongue engages the slot in the tool. Actuation of the tire changer causes the tool to rotate around the rim, in scraping contact therewith, forcing the bead off of the rim in the rotation process. Similarly, when a bead is to be forced onto the rim, the tool has a combination configuration which forces the tire bead outwardly and downwardly behind the rim while the tool again slides in scraping contact with the rim as the driving post is actuated.
Sometimes nylon caps are placed on the aforementioned combination tool to prevent the metal-to-metal scraping or scrubbing during mounting and demounting of tires from rims. Alternatively the combination tool may be coated with some type of plastic in the area of rim contact. These solutions provide only limited satisfaction since the nylon caps tend to part from the tool and the plastic coatings tend to wear away quickly.
Certain types of tire changers use a turning table and a stationary mount/demount tool. While the stationary mount/demount head may avoid custom alloy rim damage, it requires a totally distinct machine from that normally used for mounting and dismounting tires on steel type automobile wheels which operate to break the tire beads from above and below while the wheel is stationary on the machine and thereafter mount or dismount the tire bead relative to the wheel rim with a tool rotated by the rotatably driven tire tool driving post.